


Watching

by kitausu



Category: Shadowhunters (TV)
Genre: Cuddling & Snuggling, Drabble, F/M, Falling In Love, Fluff, Getting Together, Love Confessions, M/M, Multi, Threesome, Tooth-Rotting Fluff
Language: English
Status: Completed
Published: 2017-03-08
Updated: 2017-03-08
Packaged: 2018-10-01 05:12:47
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,270
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10181435
Author URL: https://archiveofourown.org/users/kitausu/pseuds/kitausu
Summary: He noticed the way Clary’s hand would rub soothing lines up and down Simon’s back as they sat in meetings. He would watch, face hot with something like jealousy when Clary would kiss Simon’s cheek whenever she left the room. Jace saw it all. And to be honest, it was probably inevitable that he would start to watch Simon, too.





	

**Author's Note:**

> I just really wanted to write this after the season finale. This is entirely self indulgent.

The whole thing was kind of a mess, and honestly, Jace kind of sometimes wished it hadn’t started at all. But, he also kind of liked the way his hand felt, tucked into Simon’s back pocket, squeezing him, pulling him close, feeling the threat of fangs against the tender skin of his lips. And wasn’t that a whole level of kink he didn’t know he had, and maybe wished he didn’t, if it didn’t feel so amazingly good.

 

After deciding that he couldn’t tell Clary about Valentine’s lie, he still hadn’t been able to keep his gaze away. They were everywhere. Simon and Clary holding hands over dinner, kissing in the hallway, laughing at some joke while they cuddled in the library. Jace couldn’t get away, even if he wanted to.

He noticed the way Clary’s hand would rub soothing lines up and down Simon’s back as they sat in meetings. He would watch, face hot with something like jealousy when Clary would kiss Simon’s cheek whenever she left the room. Jace saw it all. And to be honest, it was probably inevitable that he would start to see Simon, too.

He saw the way Simon would instinctively turn to smile at Clary whenever she walked into the room, often one fang accidentally peeking out in his excitement. The images were frequent and he caught them all. Simon trying to be discrete as he snuck sips of blood from a thermos so as not to make others uncomfortable. Simon, tripping down the stairs, despite his supernatural grace. Simon babbling about nothing, and assuming that he and Jace were friends now that Jace had saved his life.

“Why are you doing this?” Jace snapped at him one day, cutting Simon off mid-Star Trek ramble.

“Doing what?” Simon looked bewildered as Jace’s face only grew more heated.

“You two are constantly around, being lovey dovey, rubbing it in my face that I let her go, that I let Valentine trick me! I—“

Jace stopped abruptly, quickly playing back his words in his own mind as Simon’s eyes grew wide with realization.

“What do you mean, Valentine tricked you?”

“Nothing.” Jace’s voice was gruff as he turned on his heal to storm off, but Simon was faster.

The iron grip around Jace’s bicep was a sudden reminder that Simon, goofy ridiculous Simon, was still a supernatural creature with supernatural strength.

“Jace, are you not Clary’s brother?”

Jace continued to stand there, looking up at the ceiling, feeling the cold press of Simon’s undead skin through the layer of his shirt.

After a moment, and without saying a word, Jace jerked his arm free from Simon’s hold and stormed out.

He figured that was the end of it. Simon wouldn’t jeopardize his relationship with Clary by telling her. Things would just continue on the way they were.

Except, they didn’t at all.

Simon’s eyes were constantly on him now, calculating and uncharacteristically serious. He could feel them drilling into the back of his neck as he walked through the Institute, weakening his resolve, though against what, Jace wasn’t sure.

Maybe Simon was just waiting to see if Jace would out him, but there was no way he could. He couldn’t hurt Clary like that.

But then he caught them, whispering together in one of the lesser used hallways of the Institute, Clary’s eyes wide with shock and realization when he turned the corner. Simon looked bizarrely triumphant, his lips quirked up in a smile.

Jace fled and no one came after him.

It was days later when he ran into Simon, lurking like a creep outside of Jace’s door.

“Hey.”

Simon offered him hesitant smile, but Jace blew right past, trying to make it to his room before Simon could say anything.

“Hey, Jace wait!”

Simon grabbed the door before it could be slammed in his face, shoving it with enough force that Jace had to either let go or let it snap between them.

“What do you want?”

He was trying to look guarded, make Simon feel off balance enough to leave him alone. He didn’t want to have whatever conversation this was.

Simon definitely looked unbalanced, but his eyes were focused on Jace’s left ear and not really paying attention. They stood in silence for so long, Jace nearly reached for the door again before a look of determined resolved crossed Simon’s face and he darted forward and kissed him.

Jace blinked in surprise, his hands going instinctively to Simon’s hips to steady him as he felt them both start to tip backwards in the rush.

Simon’s eyes were clenched shut, but his lips were moving against Jace’s in a way that was shockingly nice, and distracting enough to have Jace pulling Simon closer and forgetting for a moment why this shouldn’t be happening at all.

Simon was the first to pull back, his cheeks flushed a little from the blood he had drank that morning.

“So, yeah, you should definitely um…let me do that again sometime. And Clary! You should let Clary do it, too. We could, you know, even all three…do it together sometime. By ‘it’ I mean kissing! I mean…we could do other stuff to, but maybe work up to it? I’m sure adjustment will…”

He trailed off a bit as he watched the play of emotions across Jace’s face. He finally settled on what looked like confusion, but his hands were still gripping the curve of Simon’s hip, so he counted that as a win.

“Are you inviting me to have a threesome?”

Simon’s nose crinkled up slightly at that, clearly unhappy with Jace’s word choice.

“I mean, sort of? We were kind of hoping for a threeway relationship, not just…you know, sex stuff. Not that sex wouldn’t be nice but, that’s not all we were wanting.”

Simon wiggled as if he wanted to move away in embarrassment, but Jace held him firmly in place, even pulling him a bit closer.

“Why isn’t Clary with you, then?”

The flush of borrowed blood in Simon’s cheeks went darker as he avoided Jace’s gaze on that one.

“Well, you see…you and Clary have already been together. And we didn’t want you to get the wrong idea, and I guess I wanted to make sure you liked me like that, and I didn’t really want Clary to see us fight if you didn’t, so we thought it would be better if I came alone.”

 _Did_ Jace like Simon like that?

The fact that his hands were still gripping his hips, massaging this thumbs subconsciously into the little dip made by the bone, sort of leaned heavily on yes.

He ended up letting Simon into his room after only a beat of hesitation. He watched as Simon texted Clary and she joined them not long after, like she had been waiting around the corner for a green light.

It was weird, kissing Clary in front of Simon, and even stranger kissing Simon in front of Clary. He did find, however, that now that he was included, the hot swirl in his stomach that always accompanied the image of Clary and Simon together, felt more like desire then jealousy anymore.

The three of them ended up curled up in Jace’s bed, Jace in the middle, much to Clary and Simon’s insistence because _you need to know we both want you!_

It was nice, feeling the cool press of Simon’s chest against his back, and the hot feel of Clary curled into his front. In fact, he could see how he could easily get addicted to something like this.


End file.
